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Topic: The 2017 melting season (Read 566974 times)

every other post is about extent which right now is the worst indicator of them all.

i know i used the example last year already but do it again as to extent:

a theoretical 1cm thick ice cover with gapps not higher than 15% grid would todaycount as 100% extent and be gone overnight. we should put into account that as thin as the ice is in general it could be that only bottom melt alone could make it melt into oblivion, probably slightly exaggerated but still not so far of IMO.

what bothers me most in the endless extent discussion is the importance most users give to the ranking of said extend which in itself has a low ranking when it comes to assessing the current state of the ice as well as the near and mid-term future o the same.

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Jaxa sea ice thickness image has and is showing a big lump of very thick ice at the pacific end of the CAB. From whence it came?

I don't know how JAXA derives these ice thickness maps, AMSR is not able to measure thickness directly, it is affected by ice thickness less than 0.5m if I remember correctly, beyond that I think it would be the effect of thickness on temperature at some times of the year which would give an indication of thickness from AMSR output.The rapid changes in "thickness" which occur in these plots frequently (including on landfast ice which isn't compacting shows that this would have to be used with a lot of caution and in the light of a better understanding of what its actual inputs are. I suspect these are effects of weather / atmosphere rather than something happening with the ice.In short don't take these maps at face value, I doubt they are intended for lay persons such as us.

Well put Andreas T,What is so bad is that whatever the problem that caused that, also affected the volume chart as well, showing a big uptick for early June. I think maybe Wipneus has this automated and it's no reflection on him. All he or his program can do is go by the data that is input. We do have to use discernment, though. There has not been enough FDD's obviously for that kind of thickness growth.CMEMS shows what JAXA has as the thickest(Beaufort/Chukchi area) as being around 1.5 meters. Some in the CAA may actually be thicker but not close to five meters.

Of som einterest wrt the impressive snow cover in Siberia: at the coastal town Tiksi in Laptev Sea, the snow depth currently is an impressive 36 cm (!)

At Sneznogorsk at the Kola peninsula in western perifery the snow depth is an outstanding 73 cm(!!!) And this is also clearly revealed by MODIS from EOSDIS NASA. (didn't VeliAlbertKallio talk about that area?)

Overall, the snowcover remains to be sigificant over the Russian Arctic and the question is for how much longer it will resist melting? And how will all the melted fresh water affect the Arctic when it reaches the ocean?

My interpretation is that ice which is thinning by bottom melt is pushed below the surface by its snow load. The snow is melted away by seawater from the floe edge inward. That the snow does not disappear quickly as soon as the ice sinks must be due to low air temperatures.Does this make sense?

The snow does not melt because the seawater is not warm enough to melt it. It just sits there. Until the seawater temperature rises above 0C it can't melt the snow.

My interpretation is that ice which is thinning by bottom melt is pushed below the surface by its snow load. The snow is melted away by seawater from the floe edge inward. That the snow does not disappear quickly as soon as the ice sinks must be due to low air temperatures.Does this make sense?

The snow does not melt because the seawater is not warm enough to melt it. It just sits there. Until the seawater temperature rises above 0C it can't melt the snow.

a snowball in salt water will melt through mixing and diffusion (osmotic pressure) even below 0C

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“You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird... So let's look at the bird and see what it's doing -- that's what counts.” ― Richard P. Feynman

Of som einterest wrt the impressive snow cover in Siberia: at the coastal town Tiksi in Laptev Sea, the snow depth currently is an impressive 36 cm (!)

At Sneznogorsk at the Kola peninsula in western perifery the snow depth is an outstanding 73 cm(!!!) And this is also clearly revealed by MODIS from EOSDIS NASA. (didn't VeliAlbertKallio talk about that area?)

Overall, the snowcover remains to be sigificant over the Russian Arctic and the question is for how much longer it will resist melting? And how will all the melted fresh water affect the Arctic when it reaches the ocean?

I've decided to compare the Wetterzentrale image of NH snow cover (based on NCEP data) with the one produced by the National Ice Center based on IMS data. It's clear that the latter shows more snow than the former, although I must add that the Wetterzentrale image is from June 10th and the NIC one is from June 9th.

Both are displayed on the ASIG front page (scroll down to the Snow Cover category).

The ECMWF forecast for the next 6 days shows a couple more days of high pressure over the Beaufort Sea, less strong than what we've seen the past two weeks, but still at 1025 hPa. After that SLP is going down, but a weak Dipole Anomaly remains in conjunction with some low pressure over on the Siberian side of the Arctic.

Wet snow now in Kimmirut at -0.1C. Quite different situation compared to last year when the snow on the hills was almost gone by this time of the year. The sea ice seems to be in a better condition as well.

If you look at just extent alone, it will give you an idea . Maybe after last winter, some of us had unrealistic expectations as to the rate of melt for this season. That is no reason not to see where we are now.

Figure 1. Arctic sea ice extent in 2007 (dark blue), 2012 (dashed dark green) and 2017 (light blue). The heavy grey line is the 1981 – 2010 median ice extent. Regions lying below the light grey shaded area are below the lowest 10% of measured values. This year has featured a lower extent than 2007 and 2012 thus far, but other years—2010, 2015 and 2016 (not shown)--have featured even less extent in early June. Image credit: NSIDC.

(b) Kimmirut and Iqaluit are on inlets with big tides but little current. The large tides make the ice pile up on itself. It's beautiful to ski through the rough ice. It also takes a long time to thaw and there's nothing to drag the ice away from town.

Koojessee Inlet in Iqaluit is only just starting to break up this weekend, according to photos a friend just posted to Facebook. One weekend ago, friends were still snowmobiling on Frobisher Bay. However, when I flew down to Montreal way back on May 1, water in Tarr Inlet (just outside Iqaluit) was starting to pond on the ice and Hudson Strait was already breaking up.

This is a pretty normal timescale. Last year the inlet apparently broke up in mid-May, which was early. The first shipment arrives in late June / early July, depending on the order that the ship visits the various Baffin Island communities (my household goods should be on that first boat, but I misread the schedule -- so they'll be on the second boat).

If some is wondering about it, it should be to understand that Thickness is meassured by the ice emissivity (something arround 50-100 GHz), while during Winter its working good, in melt saison this could lead to spurios estimates of ice Thickness.

Warming up all round now, as can be seen on the DMI sea surface temperature anomaly map (see below), in the Bering, of course, but also in the ESS and in the North Atlantic. In a couple of days I'll post a comparison with 2012 and 2016.

Both the Bering Sea and the Barents are warmer than they should be for this time of year.Not to mention, almost everywhere else.Anomaly sea surface temperature setting on Earth N.S..

These are significant anomalies over large parts of Bering Sea. Not to forget that there is constant current pushing this warmer water to Chukchi Sea. Currently Earth.nullschool is showing current speed about 900 m per hour at Bering Strait. Also sea ice area is lowest in recent history over Chukchi Sea. Currently sea ice area is about 320,000 km² (black line); same level as July 5, 2016 (red line) or July 20, 2012 (orange line). We have almost full month before July for Chukchi Sea to absorb heat from above and import warmer water from Bering Strait.Image: https://sites.google.com/site/arctischepinguin/home/amsr2/grf

Warming up all round now, as can be seen on the DMI sea surface temperature anomaly map (see below), in the Bering, of course, but also in the ESS and in the North Atlantic. In a couple of days I'll post a comparison with 2012 and 2016.

This is my biggest fear for this summer. Just how much heat will the Ocean up there manage to soak up before the energy departs again in Autumn? If last winter was dominated by the heat the ocean absorbed last summer then we can do without a repeat this time!!!

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Wind forcing increases turbulent dissipation seven times in the upper 50 m, and doubles heat fluxes at the ice-ocean interface. The presence of warm Atlantic Water close to the surface increases the temperature gradient in the water column, leading to enhanced heat flux rates within the pycnocline. Steep topography consistently enhances dissipation rates by a factor of four and episodically increases heat flux at depth. It is, however, the combination of storms and shallow Atlantic Water that leads to the highest heat flux rates observed: ice-ocean interface heat fluxes average 100 W m−2 during peak events and are associated with rapid basal sea ice melt, reaching 25 cm/d.

Of som einterest wrt the impressive snow cover in Siberia: at the coastal town Tiksi in Laptev Sea, the snow depth currently is an impressive 36 cm (!)

At Sneznogorsk at the Kola peninsula in western perifery the snow depth is an outstanding 73 cm(!!!) And this is also clearly revealed by MODIS from EOSDIS NASA. (didn't VeliAlbertKallio talk about that area?)

Overall, the snowcover remains to be sigificant over the Russian Arctic and the question is for how much longer it will resist melting? And how will all the melted fresh water affect the Arctic when it reaches the ocean?

36cm can be gone within 48h under the right conditions in this i know for sure because i've witnessed that many times during the 50 years i have been living in the swiss alps, so for me 36cm sound quite non-spectacular or did i miss the point? let me know if so.

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Really. 73 cm is just over 2 ft. Not out of the ordinary for that location this time of year, especially since Northern Europe has been seeing more snow over the last few years due to climate change. That can happen over a few hours and be gone in a couple days.

If some is wondering about it, it should be to understand that Thickness is meassured by the ice emissivity (something arround 50-100 GHz), while during Winter its working good, in melt saison this could lead to spurios estimates of ice Thickness.

It seems that the JAXA sea ice thickness product is based on brightness temperatures over sea ice, using microwave frequencies of 6 and 36 GHz:

Those "thickness" calculations seem to be quite sensitive to weather conditions (clouds, precipitation, temperature etc?) and perhaps also to other factors such as snow depth and surface wetness. So indeed, it's probably best to take it with a grain of salt, especially during the melting season.

seaicesailor

Really. 73 cm is just over 2 ft. Not out of the ordinary for that location this time of year, especially since Northern Europe has been seeing more snow over the last few years due to climate change. That can happen over a few hours and be gone in a couple days.

The question is not how fast can it go but how long it has been persisting. Like three or four weeks closer to the solstice. That is not ordinary.

Really. 73 cm is just over 2 ft. Not out of the ordinary for that location this time of year, especially since Northern Europe has been seeing more snow over the last few years due to climate change. That can happen over a few hours and be gone in a couple days.

The question is not how fast can it go but how long it has been persisting. Like three or four weeks closer to the solstice. That is not ordinary.

From his post, it just fell. And since the temperature is now over freezing, it won't persist long.And yes, it is totally within recent experience.

Let me get this right, you are trying to claim that a single unremarkable snowfall somehow is an indication of what?

Among other places, parts of the CAA continue to experience a surface wind above freezing. Some areas today are as high as 3oC and will go as high as 5o over the next couple of days, as this seems to be an ongoing occurrence. Not a big dealeeo by itself, but add a little insolation, and voila, no mas heilo.

While some of you don't find the snow cover not too reamarkable you ought to remember that many stations tend to be located in valleys or places at lower heights. At higher elevations, temps uses to be lower as well as the snow cover there uses to be thicker. Just take a tour at EOSDIS NASA and compare the valleys to the more mountainous areas. Especially the areas close to the coast should be of particular interest.

From his post, it just fell. And since the temperature is now over freezing, it won't persist long.And yes, it is totally within recent experience.

Let me get this right, you are trying to claim that a single unremarkable snowfall somehow is an indication of what?

There is still snow across the east Siberian Arctic coast, when there has not been at this date since 2006. That is snow that has accumulated over the entire winter, not "a single unremarkable snowfall". Also, do not fall into the trap of thinking that because global warming is occurring, that all events relating to things warming up (snow melting, heat waves, ice melting) must be unusually strong. If no strong heatwave appears, it will last much longer than two or three days.

But then we have soggy mud across the whole region exposed to the two weeks of peak insolation. Ever been on tropical islands anywhere near the wet season? Set your clock by the afternoon thunderstorms. Then next morning the evaporation ramps up. By early afternoon the convection cells have organised and its all on again at four when you're gathered in a bar for a couple hours of torrential downpour. And drinking. Difference here is the nights a little longer. Middays a month with more insolation per sqm of darker ground. Mr coriolus has far bigger muscles to the sth is shedloads of heat begging to be whistled up to bundle up that lighter than air water vapour and to the nth a very hungry heat sink condenser thirsty to receive it.

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My apologies to the users, I uploaded the wrong gif. I deleted that post. Here is the one I wanted to share.

This is in the Chukchi Sea ESS area. In 2016 the pack seems a blueish tinge while in 2017 it is completely white. I think the blue is either melt ponds or maybe just ice without snow cover. To me the whiteness of 2017 signals a good amount of snow. I think that is a good sign.

My apologies to the users, I uploaded the wrong gif. I deleted that post. Here is the one I wanted to share.

This is in the Chukchi Sea area. In 2016 the pack seems a blueish tinge while in 2017 it is completely white. I think the blue is either melt ponds or maybe just ice without snow cover. To me the whiteness of 2017 signals a good amount of snow. I think that is a good sign.

With the absense of meltponds so far t least there is one factor retarding melt. But the 2017 image is still much darker because of all the open water - There's also a lot of ice on the Siberian side that appears greyish, all along the margin of the fast ice and has for months, maybe because its very thin and fractured. I fear absence of meltponds is not going to be enough to save the situation

The 2 images are from june 11 - even if the coast remains ice bound open water has appeared beyond the fast ice already along much of the northern route

From his post, it just fell. And since the temperature is now over freezing, it won't persist long.And yes, it is totally within recent experience.

Let me get this right, you are trying to claim that a single unremarkable snowfall somehow is an indication of what?

There is still snow across the east Siberian Arctic coast, when there has not been at this date since 2006. That is snow that has accumulated over the entire winter, not "a single unremarkable snowfall". Also, do not fall into the trap of thinking that because global warming is occurring, that all events relating to things warming up (snow melting, heat waves, ice melting) must be unusually strong. If no strong heatwave appears, it will last much longer than two or three days.

This cloudless image from june 10 shows areas of "grey mush" between the large, and bright white icefloes in the Beaufort. What is that stuff?

My thinking was that the grey mush is thin "glue" ice on its way to early melt, but scrolling through Worldview gives the impression that after it disappears it sometimes makes a comeback. Could it possibly be fog or something?

Current ECMWF 00z op run is highly interesting and depicts a potential for two intensive cyclones at sub-980 hpa to enter parts of the CAB during the next 10 days. And that also includes a weak dipole too!

Current ECMWF 00z op run is highly interesting and depicts a potential for two intensive cyclones at sub-980 hpa to enter parts of the CAB during the next 10 days. And that also includes a weak dipole too!

This might go in the stupid questions instead, but - where can I see the ECMWF runs? Another link to bookmark.

No doubt, the positive snow anomaly is having an impact on the melt season. Snow covering ground has the same effect as ice covering water. The increased albedo will result in less warming.

With more open ocean, increased snowfall is a new, persistent feature of a warming Arctic. Not all of the effects will be positive. I worry about the insulating effects of early Fall snow cover on the permafrost but that is for a different thread.